Localized Electrochemical Corrosion Behavior of the Interface of Hot-dip Galvanized Coating

被引：0
作者：
Lin X.-L. [1 ,2 ]
Wang Y.-B. [1 ,2 ]
Xin Y.-C. [1 ,2 ]
Gao F. [1 ,2 ]
Wei Y.-Z. [1 ,2 ]
Fujita T. [1 ,2 ]
机构：
[1] Guangxi Key Laboratory of Processing for Non-Ferrous Metallic and Featured Materials, Guangxi University, Nanning
[2] School of Resources, Environment and Materials, Guangxi University, Nanning
来源：
Surface Technology | 2022年 / 51卷 / 09期
基金：
中国国家自然科学基金;
关键词：
corrosion behavior; hot-dip galvanized; interface; localized electrochemistry; scanning electrochemical microscopy (SECM);
D O I：
10.16490/j.cnki.issn.1001-3660.2022.09.022
中图分类号：
学科分类号：
摘要：
This work aims to explore the localized electrochemical characteristics and corrosion behavior of the Zn coating/steel substrate interface of the hot-dip galvanized steel. The evolution of the localized electrochemical current of the Zn coating/steel substrate interface in the 0.1 mol/L NaCl solution is studied by scanning electrochemical microscope (SECM). The distribution and composition of corrosion products are analyzed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), 3D microscopy, and X-ray diffraction (XRD). In the corrosion process, the corrosion products are mainly distributed on the surface of the steel substrate close to the interface of coating/steel substrate, and the corrosion products are less distributed on the surface of Zn coating. XRD results show that the corrosion products are mainly composed of Zn5(OH)8Cl2, Zn5(OH)6(CO3)2 and ZnO. The SECM reduction current of the steel substrate (I=1.2) is larger than that of the Zn coating (I=1.1) at the beginning of corrosion, and the whole reduction current of the Zn coating and steel decreases with the prolonging of corrosion time. There is a current depression area (I=1.0) on the steel substrate close to the interface, indicating that the corrosion products are mainly deposited in this area and play a protective role in the steel corrosion. In addition, oxygen consumption mainly occurs on the steel substrate area during the corrosion process. With the prolonging of corrosion time, the dissolved oxygen content on the coating and steel substrate gradually decreases. During the process of immersion corrosion, the Zn coating acts as an anode, dissolving to generate Zn2+ and spreading to the steel substrate area. At the same time, the OH－ forms on the surface of the steel substrate by the oxygen reduction, and diffuses to the Zn coating area. Zn2+ combines with OH－ and other ions in the solution to form corrosion products, which will deposit on the steel substrate near the interface of coating/steel substrate, and play a protective role in the steel substrate. © 2022, Chongqing Wujiu Periodicals Press. All rights reserved.
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页码：217 / 225
页数：8
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